Fabrication of an organic photovotaic device (OPV) partially via drop-on-demand inkjet printing on glass substrate

Abstract

Organic photovoltaic devices (OPV) is a very promising owing to their potential of providing environmentally safe, flexible, lightweight, and inexpensive photovoltaic technology. There are, however, some issues in a economic production of this type of photovoltaic devices, currently mainly produced via vacuum-based technologies used in the deposition, which require high investments and, therefore, high throughput to decrease the share of manufacturing cost in the final product. Thus, vacuum evaporation can be seen as a transitional deposition technology that will be partly or totally replaced by more cost-efficient, solution-based deposition technologies such as printing. The potential for lowered fabrication costs that result from the solubility of polymer-based OPV materials in common solvents has been the motivation for their use. The main advantages of printing as a deposition method include the high speed of fabrication, low material wastage, well established deposition technologies, possibility for direct patterning of the printed films, and the low processing temperatures that enable the use of flexible substrates. The most commonly used printing-deposition techniques in OPV device processing to date is drop-and-demand inkjet printing among others as gravure printing and slot die coating. In the last two decades inkjet printing passed from the field of graphic art industry to that of organic and flexible electronics, as a manufacturing tool, becoming a major topic in scientific research. The appeal of this kind of technology is mainly due to its low cost, non-contact and additive approach, which makes it surely the most promising technique over the other technologies of Printed Electronics. The focus of this work is to show, that in fact inkjet technology can be applied to deposit functional thin films for OPV devices. It has shown printed hole injection layers (HIL) with PEDOT-PSS for OPV devices which had similar characteristics and power conversion efficiencies as OPV devices with spin-coated HIL layers. The first two sections of the work give a general overview about OPV technology and printing techniques. The section 3 and 4 are experimental sections and section 5 discusses briefly the conclusions about this work.